One of the most popular members of the ever popular canon of Gilbert & Sullivan operettas is H.M.S. Pinafore. Upbeat, witty, gloriously musical, with an accessible story, Pinafore has been in production for over 120 years and shows no signs of stopping. The Public Theatre production is a perfectly structured, already well-oiled machine, put together with loving care by director Ted Pappas.

Based loosely on stories from Gilbert's Bob Ballads, the plot of Pinafore is a simple, yet entertaining combination of class satire and multiple dilemmas (all which become neatly resolved, of course, with and act two surprise revelation). Ralph, a mere sailor on the H.M.S. Pinafore, is in love with the Captain's daughter, Josephine (and she with he). Josephine, however, is betrothed to stuffy upper class Sir Joseph Porter. Though Sir Joseph is concerned by Josephine's lack of interest, the Captain insists this is due to his daughter's awe of Porter's station. With the help and hindrance of the rest of the cast (including the ship's sailors; the sisters, cousins, and aunts of Sir Joseph; bumboat woman Little Buttercup; and dastardly boatswain Dick Deadeye), the two young lovebirds plot an elopement, have the plot thwarted, then reach a happy ending all in two succinct acts.

Sir Arthur Sullivan's music wasn't praised when H.M.S. Pinafore was presented in London in 1878 by the renown D'Oyly Carte Opera Company. But the popularity of the libretto soon spread to include a strong following for the score and by the time the operetta reached the United States, it was an immediate success. The lyrical collection of tunes, including ballads, comic ditties, and twists on traditional sea music, give great vigor and body to the show, helping to flesh out the characters and strengthen the story.

The score is at its best with a strong, highly talented cast of singers, and here the Public's production excels. Tenor Pedro Porro, as love struck Ralph Rackstraw, heads a list of impressive singers who not only are accomplished at the presentation of the songs, but seem to love presenting them. Larry Daggett as Captain Corcoran, Catrina Lennon as Josephine, Myrna Paris as Little Buttercup, and Bill Nolte as Dick Deadeye all are a joy to listen to and as actors they are also solid. This is not a show for subtle and nuanced acting - the cast plays it appropriately broad and tongue-in-cheek. The one weak cast member is Kenneth Garner as Sir Joseph. He sing-speaks his songs and doesn't quite keep up with the rest of the cast. A very energetic and entertaining ensemble contribute greatly to the success of this production.

The single set depicting the quarterdeck, top deck and mast of the Pinafore as well as the distant sky, by Michael Schweikardt is truly gorgeous and serves well the Public's thrust stage. Costumes by David R. Zyla are perfect and detailed. A shining star of this show is the lush sound coming from the orchestra - what a surprise it was to count only seven in the group. They are truly amazing.

H.M.S Pinafore continues at the Pittsburgh Public Theatre through March 3. For more information and tickets: call 412-316-1600 or visit www.ppt.org. A special behind-the-scenes event especially designed for families is being presented on Saturdays February 23 and March 2 before the matinee performance. On these special days kids' (7 - 17) tickets are $10, accompanying adults get 1/2 off regular ticket prices, and all are treated to an insider's look at the Pinafore production, refreshments and gift bags (pre-show presentation at 12:45pm).